Add Stylelint dependencies to ESLint config

Until the generic starter package is created:

#165

package.json

@@ -73,6 +73,13 @@
     "eslint-plugin-testing-library": "5.9.1",
     "eslint-plugin-unicorn": "44.0.2",
     "libpg-query": "13.3.0",
+    "postcss": "8.4.19",
+    "postcss-scss": "4.0.5",
+    "stylelint": "14.15.0",
+    "stylelint-config-prettier": "9.0.4",
+    "stylelint-config-recommended": "9.0.0",
+    "stylelint-config-styled-components": "0.1.1",
+    "stylelint-processor-styled-components": "1.10.0",
     "typescript": "4.9.3"
   },
   "resolutions": {

templates/stylelint.config.cjs

@@ -0,0 +1,15 @@
+/** @type { import('stylelint').Config } */
+const config = {
+  processors: ['stylelint-processor-styled-components'],
+  customSyntax: 'postcss-scss',
+  extends: [
+    'stylelint-config-recommended',
+    'stylelint-config-styled-components',
+    'stylelint-config-prettier',
+  ],
+  rules: {
+    'no-descending-specificity': null,
+  },
+};
+
+module.exports = config;